Combining Themes On A Cake

I think one of the the hardest parts of cake decorating for me is finding a way to combine themes. Maybe it is because I really don't like combining themes on a cake! So I need help...

I have someone who wants a cake to serve between 50-75 people (don't have the exact number yet) so we are talking about 2 to 3 tiers. They want the cake to include a race track and cars, the letters A, B, and C, and some religious items.

this is just a shot in the wind buuuuuuut, if youre making a tiered cake you could make the cars race up the cake, give the cars names that start with A B C, and for the religious part the cars could have wings hahaha, just kidding.